Fixes issues when switching between software and compositing.

content/renderer/browser_plugin/browser_plugin.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef  CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_H_
 #define  CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_H_
 
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPlugin.h"
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 316 matching lines @@
   // the embedder process. It should only be updated in response to navigation
   // events in the guest.  No assumptions should be made about how the index
   // will change after a navigation (e.g., for back, forward, or go), because
   // the changes are not always obvious.  For example, there is a maximum
   // number of entries and earlier ones will automatically be pruned.
   int current_nav_entry_index_;
   int nav_entry_count_;
 
   // Used for HW compositing.
   bool compositing_enabled_;
-  scoped_ptr<BrowserPluginCompositingHelper> compositing_helper_;
+  scoped_refptr<BrowserPluginCompositingHelper> compositing_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserPlugin);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_H_